Twotter pilot, me. Ugh!
All I know about the Let I got from just watching Air Express doing engine-out training at DAUH on hot days (Hassi Messaoud, Algeria and by hot we mean 50° C). The only reason the Let climbs, seemingly, is that the Earth is a sphere! Give me a Twotter any day.
That said, the Let is a bit faster and it has air-conditioning. The Twotter designers did not pay much attention to comfort issues so that it is a pig in that regard, but I will take climb performance over comfort and speed any day.